How do I get things level and straight?
Using a spirit level properly, and why levelling to the ceiling is usually the wrong reference.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 2 min
Short answer
Check the level itself first by reversing it — a level that reads differently both ways is wrong. And do not reference floors or ceilings: in most houses they are not level, and matching them looks worse than being genuinely straight.
Most crooked shelves are not the result of carelessness but of measuring from something that was never straight. Establishing a true reference first is more than half of the job.
What you'll need
- Spirit level
- Pencil
- Tape measure
- Laser level (optional)
- Masking tape (optional)
Step by step
- Check your level is accurate.Rest it on a surface, note the bubble, then turn it end to end in the same place. The reading should be identical. If it is not, the level is wrong and everything you do with it will be too.
- Use the longest level that fits.A short level exaggerates error over distance. For a shelf, one nearly as long as the shelf. A short level on a long run is a common cause of visible slope.
- Do not reference the ceiling or floor.Very few are level. Measuring down from a sloping ceiling produces a shelf parallel to the slope, which looks deliberately crooked.
- Establish one true horizontal line first.Mark a level line with a pencil and a long level, or a laser. Everything else references that line, not the room.
- Mark both ends, then check the middle.A long run can bow. Check the level at the ends and in the middle before drilling anything.
- Use masking tape to mark on awkward surfaces.Tape takes a pencil line on tiles, glass and dark paint, and it comes off cleanly.
- Drill one hole, fix loosely, then re-check.Fix one end, swing the item to level, mark the second hole with the item in position. Far more reliable than marking both holes first.
- Step back and look.The final check. If the ceiling slopes noticeably, something perfectly level can look wrong, and a compromise between true level and matching the room sometimes looks better. Your eye decides.
Tips
- A cheap laser level is genuinely useful for shelves, pictures and tiling, and costs little. It projects a line across the whole wall at once.
- For a row of pictures, level the line rather than each frame. The eye reads the row, not the individual items.
- Phone spirit level apps are adequate for rough work and not for anything permanent. The phone case alone throws them off.
Questions people ask
How do I check a spirit level is accurate?
Read it, then turn it end for end in exactly the same place. The bubble should read identically. If not, the level is out and needs replacing.
Should I level a shelf to the ceiling?
No. Most ceilings are not level, and matching one produces a shelf that looks deliberately crooked. Establish a true horizontal and work from that.